The invention relates to a programmable positioning apparatus, and also to acceleration control systems particularly useful therein. The invention is especially suited for use in numerical control machines for precisely positioning an article, such as a machine tool or a workpiece, a programmed distance and is therefore described with respect to that application.
The productivity of a numerical control machine tool is greatly influenced by the speed at which it performs a programmed motion. On the other hand, too rapid acceleration and deceleration or too high a velocity of operation can produce shock loads, undue friction, or other effects that shorten the life of the equipment.
An object of the present invention is to provide a programmable positioning system performing a programmed motion very quickly and smoothly so as to increase the productivity of the apparatus while at the same time eliminating shock loads and excessive velocities which are liable to shorten the life of the apparatus.
Another object of the invention is to provide a novel digital acceleration control system to control the acceleration and deceleration of a driven article according to a rate which may be fixed beforehand, or which may be permitted to vary with inertia-forces, drive capability, or the like.